﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _5._10作业
{
    class Program
    {
        static void Main(string[] args)
        {
            //要求用户输入半径的值，打印出以此值为半径的圆的面积
            Console.WriteLine(  "请输入圆的半径");
            int r = int.Parse(Console.ReadLine());
            const double π = 3.14;
            Console.WriteLine("圆的面积为："+(π*r*r));
            Console.ReadKey();
        }
    }
}
